The present disclosure relates to a microchip, and particularly to a microchip for introducing a substance into a region disposed on a substrate so that chemical analysis or biological analysis is performed.
Recently, microchips having a region such as a well, a flow path, or the like for performing chemical analysis or biological analysis on a substrate such as a substrate made of silicon, a substrate made of glass, or the like have been developed by applying microfabrication technology in a semiconductor industry (see Japanese Patent Laid-Open No. 2004-219199). These microchips have started to be used in for example an electrochemical detector for liquid chromatography or a small electrochemical sensor in an actual place of medical treatment.
An analyzing system using such a microchip is referred to as μ-TAS (micro-Total Analysis System), a lab on a chip, a biochip, or the like, and is drawing attention as technology that makes it possible to achieve higher speed of analysis, higher efficiency of analysis, or a higher degree of integration as well as the miniaturization of an analyzing device and the like.
μ-TAS enables analysis with a small amount of a sample and the disposable use (single use) of microchips, and is thus expected to be applied to biological analysis dealing with very small amounts of valuable samples and a large number of analytes in particular.
An example of application of μ-TAS is an optical detecting device that introduces a substance into a plurality of regions arranged on a microchip and which optically detects the substance. Such optical detecting devices include an electrophoresis device that separates a plurality of substances from each other in a flow path on the microchip by electrophoresis and which optically detects each of the separated substances, a reaction device (for example a real-time PCR device) that allows reaction between a plurality of substances to progress within a well on the microchip and which optically detects a resulting substance, and the like.
In μ-TAS, because of a very small amount of a sample and minute regions such as wells, flow paths, or the like, it is difficult to introduce the sample into the regions accurately, the introduction of the sample may be obstructed by an air present within the regions, and the introduction may take time. In addition, air bubbles may occur within the regions at the time of the introduction of the sample. As a result, the amount of the sample introduced into each flow path, each well, or the like varies, thus decreasing analysis accuracy and decreasing analysis efficiency. In addition, when the sample is heated as in PCR, air bubbles remaining within the regions expand, and thus hamper reaction and decrease analysis accuracy.
In order to facilitate the introduction of a sample in μ-TAS, Japanese Patent Laid-Open No. 2009-284769, for example, discloses a “substrate equipped with at least a sample introducing part for introducing samples, a plurality of housing parts for housing the samples, and a plurality of air discharging parts connected to the respective storing parts, wherein at least two or more of the air discharging parts communicate with one open channel having one opened terminal.” In this substrate, the air discharging parts are connected to the respective housing parts. Thereby, when a sample is introduced from the sample introducing part into the housing parts, an air present in the housing parts is discharged from the air discharging parts. Thus, the housing parts can be smoothly filled with the sample.